For example, generally, a scooter-type motorcycle has a specific structure such that an entire structure of a vehicle body of the motorcycle is covered by a body cover, a body portion between a handle and a front portion of a rider's seat is downwardly bent largely in almost U-shape to form a foot moving space in a width direction of the vehicle body of the motorcycle, and a low-floor type foot step on which rider's foot are rested is formed to the bottom of this U-shaped bent portion on each lateral side.
In the case of a scooter-type motorcycle having a small size, its engine is generally arranged below a rider's seat, but in the case of a scooter-type motorcycle having a medium or large size, it is necessary to mount a large-sized power unit including an engine, and for this reason, the engine is generally disposed below a foot-step.
On the other hand, in accordance with a requirement for mounting a large-sized engine, many vehicles and motorcycles have been equipped with water-cooling (-cooled) engines in order to achieve stable cooling performance and noise reducing performance. In addition, a radiator or radiator unit for cooling a cooling water is arranged directly behind a front wheel of the motorcycle to maximally utilize a traveling wind.
However, in the arrangement in which the engine is disposed below the foot-step and the radiator unit is disposed directly behind the front wheel, a head portion of the engine takes a position near the radiator unit. Thus, it becomes difficult to carry out, for example, maintenance working such as exchanging of an ignition plug of a cylinder head in a working space behind the radiator unit.
The present invention was conceived in consideration of the circumstances mentioned above, and an object of the present invention is to provide a radiator unit of a motorcycle capable of providing a working space behind the radiator unit for easily performing maintenance working in the space.